Quartz oscillator device and its adjusting method

Abstract

PCT No. PCT/JP95/01285 Sec. 371 Date Mar. 7, 1997 Sec. 102(e) Date Mar. 7, 1997 PCT Filed Jun. 28, 1995 PCT Pub. No. WO96/32775 PCT Pub. Date Oct. 17, 1996A crystal oscillation apparatus and a method of adjusting the same, comprising a crystal oscillating circuit, a frequency adjusting element coupled with the crystal oscillating circuit, and a control circuit for controlling voltage to be applied to the frequency adjusting element. The control circuit comprises a temperature sensor, a temperature detecting section coupled with the temperature sensor, a memory device coupled with the temperature detecting section, an amplifier to which the memory device and the temperature sensor are coupled, a first D/A converter between the memory device and temperature detection section, and a second D/A converter between the memory device and amplifier. The memory device has no more than 8 control voltage setting groups. Each of the control voltage setting groups has temperature detection data, amplitude setting data and offset voltage data.

We claim: 
     
       1. A crystal oscillation apparatus comprising: a crystal oscillating circuit,   a frequency adjusting element electrically coupled with the crystal oscillating circuit, and   a control circuit for controlling the frequency adjusting element based on a temperature of the crystal oscillating circuit, wherein   said control circuit comprises: (1) a temperature sensor;   (2) a memory device having up to 8 control voltage setting groups, wherein each of the control voltage setting groups stores temperature detection data, amplitude setting data and offset voltage data;   (3) a first digital-analog converter for converting the output signal of said memory device;   (4) temperature detection means for comparing the output signal of said first digital-analog converter with up to 8 control voltage setting groups stored in said memory device, selecting and outputting one of control voltage setting groups corresponding to the output of said temperature sensor;   (5) a second digital-analog converter for converting and outputting the data stored in the control voltage setting group selected at said temperature detecting section; and   (6) an amplifier for receiving the data output from said temperature detecting section and said second digital-analog converter and for compensating the output of said temperature sensor.     
     
     
       2. The crystal oscillation apparatus of claim 1, wherein the frequency adjusting element is comprised of a plurality of varactor diodes electrically coupled with at least one of an input side and an output side of the crystal oscillating circuit. 
     
     
       3. The oscillation apparatus of claim 2, wherein a first capacitance of an input side varactor diode is equal to or higher than a second capacitance of an output side varactor diode. 
     
     
       4. The crystal oscillation apparatus of claim 2, wherein the number of varactor diodes electrically coupled with the input side and the output side of the crystal oscillating circuit is selected according to an oscillation frequency of the crystal oscillating circuit. 
     
     
       5. A crystal oscillation apparatus comprising: crystal oscillating circuit,   a frequency adjusting element electrically coupled with the crystal oscillating circuit, and   a control circuit for controlling the frequency adjusting element based on a temperature of the crystal oscillating circuit, wherein said control circuit comprises: (1) a temperature sensor;   (2) a memory device having up to 8 control voltage setting groups, wherein each of the control voltage setting groups stores temperature detection data, amplitude setting data and offset voltage data;   (3) a first digital-analog converter for converting the output signal of said memory device;   (4) temperature detection means for comparing the output signal of said first digital-analog converter with up to 8 control voltage setting groups stored in said memory device, selecting and outputting one of control voltage setting groups corresponding to the output of said temperature sensor;   (5) a second digital-analog converter for converting and outputting the data stored in the control voltage setting group selected at said temperature detecting section;   (6) an amplifier for receiving the data output from said temperature detecting section and said second digital-analog converter and for compensating the output of said temperature sensor; and     wherein at least one of i) the amplifier, ii) the first D/A converter, iii) the second D/A converter, iv) the temperature detecting section and v) the memory device performs an intermittent operation.   
     
     
       6. The crystal oscillation apparatus of claim 5, wherein a time between the intermittent operation and a subsequent intermittent operation in at least one of i) the amplifier, ii) the first D/A converter, iii) the second D/A converter and iv) the temperature detecting section is a first time, said first time being shorter than a second time between the intermittent operation and the subsequent operation in the memory device. 
     
     
       7. The crystal oscillation apparatus of claim 5, wherein the first D/A converter and the second D/A converter are each comprised of a variable attenuator. 
     
     
       8. The crystal oscillation apparatus of claim 7, wherein an output from the variable attenuator is set at a voltage not lower than 0 volts. 
     
     
       9. A crystal oscillation apparatus comprising: a crystal oscillating circuit,   a frequency adjusting element electrically coupled with the crystal oscillating circuit, and   a control circuit for controlling the frequency adjusting element based on a temperature of the crystal oscillating circuit, wherein said control circuit comprises: (1) a temperature sensor;   (2) a memory device having up to 8 control voltage setting groups, wherein each of the control voltage setting groups stores temperature detection data, amplitude setting data and offset voltage data;   (3) a first digital-analog converter for converting the output signal of said memory device;   (4) temperature detection means for comparing the output signal of said first digital-analog converter with up to 8 control voltage setting groups stored in said memory device, selecting and outputting one of control voltage setting groups corresponding to the output of said temperature sensor;   (5) a second digital-analog converter for converting and outputting the data stored in the control voltage setting group selected at said temperature detecting section;   (6) an amplifier for receiving the data output from said temperature detecting section and said second digital-analog converter and for compensating the output of said temperature sensor; and     wherein the frequency adjusting element and the control circuit are contained within a single semiconductor device.   
     
     
       10. A crystal oscillation apparatus comprising: a crystal oscillating circuit,   a frequency adjusting element electrically coupled with the crystal oscillating circuit, and   a control circuit for controlling a voltage to be applied to the frequency adjusting element, having   a temperature sensor for sensing a temperature of the crystal oscillating circuit,   a temperature detecting section electrically coupled with the temperature sensor,   a memory device electrically coupled with the temperature detecting section, said memory device having up to 8 control voltage setting groups to control the frequency adjusting element, each of the control voltage setting groups has i) temperature detection data, ii) amplitude setting data, and iii) offset voltage data,   an amplifier to which the memory device and said temperature sensor are electrically coupled,   a first digital-analogue (D/A) converter coupled between said memory device and said temperature detecting section,   a second D/A converter coupled between said memory device and said amplifier; and   a sample and hold circuit coupled between said frequency adjusting element and said amplifier.   
     
     
       11. The crystal oscillation apparatus of claim 10, wherein at least one of i) the amplifier, ii) the first D/A converter, iii) the second D/A converters, iv) the temperature detecting section and, v, the memory device performs an intermittent operation. 
     
     
       12. The crystal oscillation apparatus of claim 11, wherein a time between the intermittent operation and subsequent intermittent operation in at least one of i) the amplifier, ii) the first D/A converter, iii) the second D/A converter and iv) the temperature detecting section is a first time, said first time being shorter than a second time between the intermittent operation and the subsequent operation in the memory device. 
     
     
       13. A method of adjusting a crystal oscillation apparatus which is comprised of a crystal oscillating circuit, a frequency adjusting element electrically coupled with the crystal oscillating circuit, and a control circuit for controlling voltage to be applied to the frequency adjusting element, wherein said control circuit comprises a temperature sensor, a memory device, an amplifier coupled to the memory device and said temperature sensor, said memory device having a plurality of control voltage setting groups, comprising the steps of: (1) placing the crystal oscillation apparatus into a thermostatic chamber with a circuit between said amplifier and said frequency adjusting element in an open condition,   (2) varying a temperature of the thermostatic chamber from a low temperature to a high temperature,   (3) finding an upper limit and a lower limit of a band of control voltages, respectively, by which an oscillation frequency of the crystal oscillating circuit is within a specified tolerance range by applying a control voltage to said frequency adjusting element at each of a specified plurality of temperature zones, and   (4) plotting up to 8 straight lines from said low temperature through said high temperature to fall within said band of control voltages covering said low temperature to said high temperature determined in step (2), and writing the data produced by a) each of the up to 8 straight lines and b) outputs of the temperature sensor responsive to said low temperature through said high temperature into the memory device as i) temperature detection data, ii) amplitude setting data and iii) offset voltage data corresponding to the respective straight lines.   
     
     
       14. A method of adjusting a crystal oscillation apparatus which is comprised of a crystal oscillating circuit, a frequency adjusting element electrically coupled with the crystal oscillating circuit, and a control circuit for controlling a voltage to be applied to the frequency adjusting element, wherein said control circuit comprises a temperature sensor, a memory device and an amplifier to which the memory device and said temperature sensor are electrically coupled, said memory device having up to 8 control voltage setting groups, comprising the steps of: (1) placing the crystal oscillation apparatus into a thermostatic chamber with a circuit between said amplifier and frequency adjusting element in an open condition,   (2) varying a temperature of the thermostatic chamber from a low temperature to a high temperature   (3) finding an upper limit and a lower limit of a band of control voltages, respectively, with which an oscillation frequency of the crystal oscillating circuit is within a specified tolerance range by applying a control voltage to said frequency adjusting element at each of a specified plurality of temperature zones, and   (4) plotting up to 8 straight lines from said low temperature through said high temperature to fall within said band of control voltages covering said low temperature to said high temperature determined in step (2), and writing the data produced by a) each of the up to 8 straight lines and b) outputs of the temperature sensor responsive to said low temperature through said high temperature into the memory device as i) temperature detection data, ii) amplitude setting data and iii) offset voltage data corresponding to the respective straight lines.   
     
     
       15. The method of adjusting a crystal oscillation apparatus as claimed in claim 14, wherein a switch is provided between the amplifier and the frequency adjusting element, and an external voltage input terminal is electrically coupled between the switch and the frequency adjusting element. 
     
     
       16. A crystal oscillation apparatus comprising: a crystal oscillating circuit,   a frequency adjusting element electrically coupled with the crystal oscillating circuit, and   a control circuit for controlling the frequency adjusting element based on a temperature of the crystal oscillating circuit, wherein said control circuit comprises: (1) a temperature sensor;   (2) a memory device having up to 8 control voltage setting groups, wherein each of the control voltage setting groups stores temperature detection data, amplitude setting data and offset voltage data;   (3) a first digital-analog converter for converting the output signal of said memory device;   (4) temperature detection means for comparing the output signal of said first digital-analog converter with up to 8 control voltage setting groups stored in said memory device, selecting and outputting one of control voltage setting groups corresponding to the output of said temperature sensor;   (5) a second digital-analog converter for converting and outputting the data stored in the control voltage setting group selected at said temperature detecting section;   (6) an amplifier for receiving the data output from said temperature detecting section and said second digital-analog converter and for compensating the output of said temperature sensor; and     wherein said control circuit further comprising:   a temperature detecting section coupled with the temperature sensor,   a memory device coupled with the temperature detecting section,   an amplifier coupled to the memory device and said temperature sensor,   a first digital-analog (D/A) converter coupled between said memory device and said temperature detecting section, and   a second D/A converter coupled between said memory device and said amplifier.   
     
     
       17. The crystal oscillation apparatus of claim 16, wherein the amplifier is comprised of a variable attenuator and an amplifying circuit. 
     
     
       18. The crystal oscillation apparatus of claim 17, wherein an output from the variable attenuator is set at a voltage not lower than 0 volts. 
     
     
       19. The crystal oscillation apparatus of claim 16, wherein a switch is provided between the amplifier and the frequency adjusting element, and an external voltage input terminal is electrically coupled between the switch and the frequency adjusting element. 
     
     
       20. A crystal oscillation apparatus comprising: a crystal oscillating circuit,   a frequency adjusting element electrically coupled with the crystal oscillating circuit, and   a control circuit for controlling the frequency adjusting element based on a temperature of the crystal oscillating circuit, wherein   said control circuit comprises: (1) a temperature sensor;   (2) a memory device having a plurality of control voltage setting groups, wherein each of the control voltage setting groups stores temperature detection data, amplitude setting data and offset voltage data;   (3) temperature detecting means for comparing the output signal of said temperature sensor with a plurality of control voltage setting groups stored in said memory device, selecting and outputting one of control voltage setting groups corresponding to the output of said temperature sensor; and   (4) an amplifier for generating a polarity, a gradient and an offset of a compensation straight line to compensate the output signal of said temperature sensor, based on the data stored in the control voltage setting group selected at said temperature detecting section.